Surgical procedure for meniscus punch defects

Rabbit animal models have been described and are validated models for testing of menisci treatment in the avascular zone [11–13]. Similar to untreated human menisci, untreated defects in the avascular zone or filling with a cell-free implant showed no tendency for healing [11]. The procedures were approved by the Institutional Animal Care and Use Committee at our institution.

Twelve New Zealand White rabbits (5-month-old males) were used in this study. The rabbits were anesthetized and exposure of the lateral joint compartment was achieved by a lateral parapatellar arthrotomy. Using limited soft tissue release, the lateral meniscus was luxated anteriorly and avascular meniscal defects made by using a 2-mm punch device (Stiefel, Offenbach am Main, Germany).

On the one side, the punch defect was treated by an autologous MSC matrix composite and, on the contralateral knee, the punch defect in the lateral meniscus was filled with an autologous meniscal cell matrix composite. Fixation was achieved by press-fit implantation of the cell-matrix constructs. Following relaxation of the meniscus, the joint capsule was reattached and skin closure was achieved. Postoperatively the animals were allowed free movement without use of any immobilization.

The animals were sacrificed at 6 or 12 weeks; each group consisted of 6 New Zealand White Rabbits.